Urodynamics is the study of the pressure in the bladder and how it reacts as it fills up. People with spinal injury should undergo this study on an annual basis to ensure that problems with the bladder will not affect the heath of the kidneys. Urologists who order this test will usually want patients to take the same dose of bladder relaxant medicine such as Detursitol or Ditropan. This is to see how the bladder reacts under everyday contidions.

Two very thin tubes will be inserted into the bladder via the urethra. One is to fill up the bladder with sterile saline solution. The other is a sensor to monitor the pressure in the bladder. Another sensor will be inserted into the rectum. All these are connected to a machine to record the data. Before the procedure begins, the patient is asked to cough to determine how much pressure is exerted in the bladder and rectum.

During the procedure, the saline will be pumped into the bladder at a predetermined rate. The patient has to inform the technician running the procedure when he first feels the desire to urinate. Saline will continued to be pumped into the bladder until it can no longer hold the saline and starts to leak. The pressure and volume of saline inside the bladder is recorded. The amount of saline that leaked out is also recorded. After that, the technician will pump out the saline to measure the amount that is still inside the bladder.

The procedure will then be repeated with another predetermined rate of saline flow. The technician who did my procedure started with 30ml/min for the first study and 15ml/min for the second. I started to leak at around 310ml when the pressure in the bladder rose to slightly more than 50cmH2O. The volume of saline that remained in the bladder after voiding was around 200ml.

The urologist said that he was not too concerned with the figures. It probably would not cause much damage to the kidneys and I was to continue with the 3 hourly intermittent catheterisation and the prescribe dosage of Detrusitol. He recommended that I repeat the procedure biennially. Antibiotics is usually prescribed after the procedure to prevent urinary tract infection.